One known technique for measuring a concentration of atmospheric grade ozone involved flowing a stream of gas along a chamber and measuring a difference of temperature between a reference temperature value at an upstream position of the chamber using a thermistor and measuring an instantaneous temperature value at a downstream position of the chamber using a catalyst-covered thermistor. As the stream of gas flows along the chamber, the ozone of the stream of gas that comes into contact with the catalyst-covered thermistor can decompose in an exothermic reaction which causes heating of the catalyst-covered thermistor and increasing of the difference of temperature. The evaluation of the concentration of atmospheric grade ozone can depend on various parameters such as gas pressure, flow rate, instantaneous positions of the thermistors within the chamber, etc.
Furthermore, one known technique for measuring a concentration of industrial grade ozone involved dividing a stream of gas into a reference stream which remains unaltered and a measurement stream which entails an exothermal decomposition of ozone into oxygen by the passage through a bed of activated charcoal. To suitably compare the reference stream and the measurement stream, the latters have to exhibit relatively similar temperature and pressure values. However, since the chemical decomposition of the ozone tends to generate an excess of heat within the measurement stream, the latter generally has to be cooled down to the temperature of the reference stream using iced water baths prior to the comparison of their thermal conductivities and estimation of the concentration of ozone in the gas stream. Although suitable for industrial ozone grade, biases were generally introduced due to differing properties of the reference stream and of the measurement stream.
Although the techniques known in the art were satisfactory to a certain degree, there remained room for improvement. For instance, prior art techniques often required compensating for variations of pressure and temperature. In general, there remained room for improvement in terms of simplifying ozone concentration measurement.